Patent GB-1363308-A (GB)
Title: Automotove transmission
IPC: F16H61/06
Filed: 1971-11-10
Abstract: 1363308 Change-speed control BORGWAKNEB CORP 10 Nov 1971 [21 Dec 1970] 52167/71 Heading F2D In an automatic transmission on a motor vehicle, wherein output speed and enginethrottle sensitive liquid pressures C16, C18, operate 1-2, 2-3 and 3-4 shift-valves 205, 206, 207 controlling two friction clutches 32, 33 and two brakes 120, 140, selecting four forward ratios, and a manual valve 200 provides selection of a two-way manual low and reverse by applying a third brake 90, the application of that brake 90 is controlled by a manual low and reverse control valve 213 which, when the manual valve supplies line pressure C20 for low, permits that pressure C20 to reach the low brake 90 only when all the automatic shiftvalves 205, 206, 207 are in their down-shifted (left) position to supply line pressure C20 through lines C34, C33 and C26 to shift the lowreverse control valve 213 right, permitting line pressure C29 from the manual valve 200 to pass through a restrictor 414, control valve 213 and line C27 to apply the low-reverse brake 90. In this manual low setting, line pressure C29, C30, C31, supplied by the manual valve 200, acts on differential lands 303 &c. of the shiftvalves 205 ... 207 to latch them in down-shifted position. The line C26 is thus pressurized in all but reverse setting, in which it is exhausted, permitting the control valve 213 to be spring- returned left, and communicating the brake line C27 with a line C28 which receives line pressure through a reverse inhibitor valve 212 (see below) when reverse is selected by the manual valve 200. Gear arrangement.-The torque-converterdriven planet gear (Fig. 1, not shown), which is fully described, is that forming the subjectmatter of Specification 1,252,586, comprising an output sun-ring train compounded with a Simpson two-train gear-set to provide directdrive, three reduced ratios and one reverse, as follows. Manual low, by clutch 32 (engaged for all forward ratios) and brake 90; automatic low (one-way reaction), by clutch 32 alone; second, clutch 32, brake 120; third, clutch 32, brake 140; fourth, clutches 32 and 33; reverse, clutch 33, brake 90. Fluid pressure supply and regulation.- Pressure in a main line C2, fed by a single inputdriven pump 190, is regulated by a differentially-landed primary pressure regulator 203, loaded, for pressure increase, by a spring 221, opposed by pressure supplied to ports 217, 218, 219, to regulate to four different fixed levels as follows. Normal pressure is provided by supplying all these three ports with line pressure C2, C4, C5. At stall the load line C4 is exhausted, to increase regulated pressure C2, by a stall control valve 204, shifted left by a combination of low governor pressure C16 and high TV pressure C18. In reverse the manual valve 200 exhausts C5 to augment regulated pressure, and, also in reverse, action of the stall valve 204, to exhaust C4, provides the fourth fixed pressure.  Pressure C3, spilling from the primary regulator 203, feeds a differentially-landed torqueconverter pressure regulator valve 202, regulating to a torque-converter feed line C7 and from a torque-converter exhaust line C9, the latter, and spill C6, passing through a cooler 231, with by-pass 248, to a lube line C12, and through a relief valve 249 to pump suction. Transient shift pressures are controlled by a two-way acting accumulator 208 having two pistons 401, 402 separated by a spring 405, and by individual brake exhaust valves 210, 211 (see below), all subject to TV control. Shift pressures.-Governor pressure C16 is provided by an output-driven governor valve 209, not described. Throttle (TV) pressure C18 by the differentially-landed spool 271 of a TV valve 201 loaded rightwards through a spring 276 by a spool 270, influenced by the accelerator. Manual valve 200 provides settings PRND 321, Drive, D, giving automatic shifts between all four ratios; 3, between the first three; 2, the first two; and 1 the two-way first, the manual settings all being subject to governor controlled downshift inhibition. Automatic shift valves, 205, 206, 207, each have a differentially-landed main spool 301 &c. at the left, directly loaded rightwards, for upshift, by governor pressure C16, and separate spools or plugs loaded leftwards by TV pressure C18 as follows. In the 1-2 valve 205 there is a single TV-loaded end plug 302 urging the main spool 301 left, through a spring 314. In the 2-3 valve 206 a TV-loaded differentially landed spool 325 similarly acts on the main spool 324, but in its downshifted position exposes TV pressure C18 to act rightwards on its differential land. The 3-4 valve 207 has both a TV-loaded end-plug 361 and a second differentially-landed spool 351 with, in the downshift position, an additional leftward load by TV C18, which, in the upshift position, is replaced by line pressure C15. In the manual settings of the manual valve 200, line pressure C29, or C30, or C31, downshifts the respective shift valves in opposition to governor pressure C16. The shift-valves receive their servo feed pressure from the manual valve 200 in the following sequence. In all forward settings the manual valve 200 directly pressurizes a line C20 feeding the front clutch 32. In the downshifted (leftward) position of the 3-4 and 2-3 shift-valves 207, 206, this line pressure C20 passes through the valves in sequence, and through C34, C33 to the 1-2 shift-valve 205, C33 and C34 being exhausted in turn by the 2-3 and 3-4 shift valves 206, 207 when they upshift. Shift sequence 1-4 in D is as follows. Upshift of the 1-2 shift-valve 205 supplies line pressure C20, C34, C33 to C25 to engage the centre brake 120 for second ratio, engagement rate being controlled by supplying brake-apply pressure C25 to the left end of the accumulator 208 which strokes fully to the right opposed by a spring 405 and TV pressure C18. Upshift of the 2-3 shift-valve 206 connects the 1-2 valve servo feed C33 to a restricted exhaust X15 at the 2-3 valve, and supplies line pressure C20, C34, C23 to apply the front brake 140, pressure in which shifts right, in opposition to TV pressure C18, C19 an exhaust valve 211, providing an exhaust at X22 for the 1-2 valve servo feed line C33 through a line C24 connected thereto by the upshifted 2-3 shift valve 206, whereby the rate of exhaust of the releasing brake 120 is regulated by the rate of pressure increase in the applying brake 140, to a TV dependent degree. Pressure C23 applying the front brake 140 is also supplied to the right side of the accumulator 208, which now strokes left, opposed by spring and TV pressure C18. 3-4 upshift by the shift-valve 207 is similar to 2-3, except that another exhaust valve 210, similar to 211, controls the release rate of the front brake 140, and the accumulator 208, stroking back right, delays release of brake pressure C23 until the rear clutch 33 is engaged, by line pressure C20 through the shift-valve 207, restrictor 410 and line C21 which line C21 also controls the exhaust valve 210. For the downshifts the accumulator 208 modulates brake engaging pressure. First, for the 4-3 shift, accumulator stroke is resisted only by spring and TV pressure C18, whilst for the 3-2 it is additionally resisted by brake releasing pressure in C23. Manual settings.-In setting 3, the manual valve 200 supplies line pressure C2 to C15, C20 and C31, the last named, acting at port 346, causing downshift of the 4-3 shift valve 207, governor pressure C16 permitting, after which downshift is maintained by line pressure at valve ports 340, 346 and 347. 3-2-1 and 1- 2-3 automatic shifts are as in D. Setting 2 produces the same conditions as for 3 and additionally pressurizes C30, producing a similar downshift action in the 2-3 valve 206. 2-1 and 1-2 automatic shifts are as in D. Setting 1 additionally pressurizes C29, downshifting the 1-2 valve 205, as above, and also passing to the manual low-reverse control valve 213 through a restrictor 414. With the 3-4, 2-3 and 1-2 valves 207 ... 205 all downshifted, line pressure C20 passes through them all in sequence through C34, C33 and C26 to shift right the low-reverse valve 213 to supply line pressure C29 through C27 to apply the rear brake 90.  In reverse setting line pressure supplied to C32 passes through the 3-4 valve 207, restrictor 410 and line C21 to engage the direct-reverse clutch 33, the same pressure C32 also passing to the reverse inhibitor valve 212 which, if permitted by governor pressure C16, is spring moved left, passing C32 pressure through C28, the low-reverse control valve 213, now in its left position, and line C27 to apply the lowreverse brake 90.